Human Ear Freq. Range and Ad in Crutchfield

burdette

Through all of this, I don't think I've heard anyone comment on why it is that extended frequency response is supposedly a good thing. Therefore...

..say you have a tweeter that is 3dB down at 20Khz. Assuming you actually have any useful information at a frequency that high, the tweeter will attempt to recreate it, but the response will begin to fall off and be 3dB down by 20Kz. However, any OTHER characteristics of how that tweeter behaves at the limitations of its response (increased distortion, phase issues, etc), will then be occuring in a supposedly audible range.

In contrast, you have a tweeter that is 3dB down at 30Khz. When THAT tweeter begins to roll off and exhibit any other problems or quirks that occur when the response begins to fade, it is all occuring around 30Khz.. well above what we can hear. This tweeter would then, supposedly, produce the 20Khz information 'better' and without any added problems due to the driver itself.

Although not the only consideration, this same idea plays into the selection of crossover frequencies. Whether on the upward side (when to cross from W to M and M to T), or on the low side (when to cross from T to M and M to W), you want to try to avoid being near the limitations of the driver's response so you're asking the driver to perform only in a frequency range that it can handle without significant problems/distortion.

As for high frequency information... I agree with Doc that if your transducer (human ear) simply does NOT respond above a certain frequency, then any information above that frequency is superfluous.

Except for ensuring smooth response right on past the limitations of our hearing, I think claims of extended frequency response are marketing... maybe aimed at the same people who believe that any BIG speaker *must* be better than a smaller speaker. Plus...... the volume on this amp goes to 11.


Edit: Russ, same idea with electronics. If you start out trying to design an amp that is clean from 20-20k, then any potential problems that pop up near one end of the response could be within the audible range. If you instead design an amp that is clean from 1-100k, then you SHOULD avoid any 'edge of response' problems, because they occur outside the range of interest/concern.

RuSsMaN

Did we really need a Spinal Tap reference Mark?

Good points, but what if we have 2 tweeters, both extend to say, 22Khz before starting to roll off. One tweeter continues to a 26Khz 10db downpoint, the other to a 40Khz 10db downpoint. Making a gross assumption that all other things are equal in the build, what we are saying here is there would be no audible difference in the two, correct?

Since we are talking about human hearing, and the relative 20Khz mark on the top end. Is it a brick wall? Does our hearing response graph begin to fade at that point, -3db -6db, etc? I know this is speaking loosley, as more than likely no two sets of ears are identical, but I'm curious.

Cheers,
Russ

Edit to your edit: That makes perfect sense to me.

Dr. Spec

Originally posted by RuSsMaN
Re-read my last post Doc, I didn't say the harmonic was lower.

Fair enough, not arguing, just discussing.

Assuming what you said is true, the obvious question to arise is why then do we produce speakers, amps, sources etc, that extend (sometimes WELL) beyond what *most* can hear? If we can't hear it, and it doesn't affect the audio we CAN hear, the point is.....?

I understand what you are saying, but I'm still skeptical as to why it (extended response) is there in the first place, if it does nothing to/has no affect on, the end product (what hits our ears).

I'd sure like to hear Polk's take on the topic.

Cheers,
Russ

Hi Russ:

I thought you meant that by this statement, but maybe I misinterpreted what you were saying: " Agreed, but what I am still curious about, is if that freq the dog whistle is at, is the resulting harmonic of a lower, audible freq, what (if any) affect does the speakers ability to reproduce that harmonic have on the perceived sound to the listener?"

Anyway, to answer your question, I have no idea. In theory, if equipment is perfect from 0-20,000, we should be able to feel/hear everything. Why it extends way, way beyond 20,000 is beyond me.

Maybe Burdette has a point, but I think there is more to it. Maybe an EE like HBomb can shed some light.

Doc

hoosier21

waaaaa

A EE sheding light

waaaaaa

HBombToo

Originally posted by Dr. Spec


Maybe Burdette has a point, but I think there is more to it. Maybe an EE like HBomb can shed some light.

Doc

The actual points being made are actually confusing me as too what we are taalking about here but I have an example as to my take on the subject matter.

Lets take a power amp... I don't believe any design engineer uses a metric such as damping factor for a baseline design parameter; however, a biproduct of good engineering practices and components leed to excellent damping factors. Much the same in overall freq response... the higher the power the better the transistors, tubes if you will, and output transformers that are used in the device of discussion which lead to increased linearity of the the amp in question... this same arguement can be applied to speakers IMO.

I have a hard time believing any design engineer would use a metric such as 100Khz as a design goal and drive to it... the 100Khz or 70Khz in the case of the tweeter is a biproduct only and possibly a good 1. I say possibly and here comes the Caveat... it becomes a very subjective arguement outside of the lab to quatify the impact of increased bandwidth abouve what we can actually hear.

HBomb

HBombToo

Damn I can't spell for **** but I hope you get my point?

burdette

Originally posted by Dr. Spec
Maybe Burdette has a point, but I think there is more to it. Maybe an EE like HBomb can shed some light.
Doc

Wull, gee... my BSEE ain't good 'nuf fer ya?

Russ... ya, I think I'd say that in your example you couldn't hear the difference. You could MEASURE the difference...

We're throwing out 20K here as the high end, but I'll wager few of us here can still hear that high, if we ever could. And secondly, how much information *is* there up there?

The highest note on a piano is 4180Hz... we have to get to the 5th harmonic before we're in the neighborhood of 20kHz.

We can discuss Fourier approximations of pressure fuctions, if you'd like.

p(t) = a0 + a1 cos(wt) + b1 sin(wt) + a2cos(2wt) + b2 sin(2wt)
+ a3 cos(3wt) + b3 sin(3wt) + ... + an cos(nwt) + bn sin(nwt)

Different instruments produce different levels of the harmonics even if playing the same note. In other words, different instruments have different values for the a's and b's in the equation. We can move on to integrals if anyone has a yearnin'.

If you've the time....
http://www.cco.caltech.edu/~boyk/spectra/spectra.htm

HBombToo

Originally posted by burdette



Wull, gee... my BSEE ain't good 'nuf fer ya?

Nope!

I don't think Doc knew you were an engineer because you can speak and spell pretty damn good!



HBomb

RuSsMaN

Originally posted by burdette

We can discuss Fourier approximations of pressure fuctions, if you'd like.

p(t) = a0 + a1 cos(wt) + b1 sin(wt) + a2cos(2wt) + b2 sin(2wt)
+ a3 cos(3wt) + b3 sin(3wt) + ... + an cos(nwt) + bn sin(nwt)

Um, ok.

I'ma go back to practicing writing the alphabet in my Big Chief tablet now.

Cheers,
Russ

Dr. Spec

Awesome thread.

Russ, I re-read your statement about the dog whistle and I get it now. You didn't say what I thought you said.

Burdette - didn't know you were an EE because you don't advertise it like HBomb. But I should have known by the general goodness of your posts, and the Fourier equations (I hated that stuff) sealed it. No offense intended at all - always respect your posts.

Paul your statement strikes at the heart of the matter and we would all like to see further development and application of this concept. I too am very skeptical.

Doc

F1nut

Paul,

Thank you for your insight.

"Does this mean you have to drive the resonance all the way to 70K? No, 25K is plenty high enough for this purpose."

That pretty much sums it up for me and is pretty much what doro and I were thinking.

HBombToo

Originally posted by F1nut
Paul,

Thank you for your insight.

"Does this mean you have to drive the resonance all the way to 70K? No, 25K is plenty high enough for this purpose."

That pretty much sums it up for me and is pretty much what doro and I were thinking.

Stop the bus.... I think there is a sublety to what Paul stated.

With SACD and a sampling rate of what... ~2.8Mhz the accuracy and response of the 20-20Khz band is far greater than RedBook. Understood and in general agreed that it has a positive impact on what was recorded or can send to the speaker. That said, can we hear it greater than the 20-20Khz? There is the subjectivity I was referring and Paul stated.

In short then higher bandwidth electronics is good but high bandwidth speakers are the question... For me anyway? Who knows, the Japanese may be on to something.

HBomb

burdette

Is there *any* other hobby/interest/passion that has as many areas open to interpretation and opinion as audio/video? That isn't rhetorical... I thought about 'computers' as a hobby.. and certainly there are as many or more tech topics... but the results is what they is, either the machine is faster or not, better or not. Perhaps the usefulness is open to interpretation, but rarely the result.

In AV, sure, there are topics that are pretty cut and dried.. big woofers tend to move more air; distortion will kill a speaker before a little too much power; etc. But isn't it amazing.. because this *all* comes down to our individual ears and tastes.. that there can be SO many areas/topics that are open to lively discussion... wires, cables, better capacitors in crossovers, tubes vs. SS, mono block vs. combined, one brand of receiver sounds 'brighter' than another, on and on and on. Even when precise measurements can discern differences (and certainly that isn't always the case even when improvement is claimed), we don't agree on whether the differences matter - can we *hear* the differences. And even if we both heard the differences, we could easily disagree on which was better.



Doc... apparently I come off to you as offended when I'm not. You tend to sincerely apologize when I'm just bustin' your chops. Just wanted to let you know... appreciated but unnecessary. I'm relatively thick-skinned, and hopefully the tone of some of my bullshitting posts comes through even if the sarcasm is a little heavy. Hbomb is no doubt more up on EE topics than I.... although I don't think he's ever told us what college he went to. Is his degree from Grenada U? Or the Jamacian College of Engineering? He sorta sounds like a Purdue or Penn State guy. Is it all right that we're talking about him like he isn't here??

oh.. uh.. hi H... uh.. how's it hangin' man?

HBombToo

Originally posted by burdette
Hbomb is no doubt more up on EE topics than I....

I don't know about all that my friend... as a matter of fact I made it very clear on a few occasions that I don't believe my degree makes me an expert audiophile. The school of hard knocks is supercedes a degree any day IMO especially in audio.

although I don't think he's ever told us what college he went to. Is his degree from Grenada U? Or the Jamacian College of Engineering? [/B]

The Pennsylvania State University. GOOOOOOOOOOO JoePaw!
However the Missourah influence is taking its toll according to buddy Russ!


How bout you bro... you a Mizzou man?



HBomb

HBombToo

Originally posted by burdette

Is it all right that we're talking about him like he isn't here??

Yup... I have pretty think skin myself!

HBomb

burdette

So you are Penn State....? If so.. pretty good guessin' on my part.. you guys are the 'zero point one' in the Big10.1 conference. No, not Mizzou for me. My degree is from the Univ. of Iowa ('88). I'm pretty sure the school is still there. I haven't been back since graduating from grad school in Dec94, although both the college of engineering and the MBA program seem to think I should be giving them lots of money.

HBombToo

How in Gods name would you guess that??? do we all have that bad of spelling? I like the .1 though... distinguishes us Penn Staters much like .1 LFE in our rigs.

HBomb

dorokusai

That was my original point, albeit minus all the good data, is that if you can't hear it, what's the difference then.

Paul's comment about the smaller extended freq range, makes much more sense to me. A small increase in freq extension seems more useful, and believeable, than to 70Khz; in addition, entirely logical, given an SDA or LSi audition.

Studies are a dime a dozen, so I would like to know more about that Japanese experiment.

But back to the start of the thread,

"Do you think it is a misleading ad?", or would you say its just normal advertising hype???

HBombToo

Yes! but I'm that with with most claims.

HBomb

dorokusai

HBombToo

Originally posted by dorokusai

point in case... do we or not kick the living snot out of Lucent when we get the chance?

kNo what I mean vern?

HBomb

ncw

Originally posted by Paul DiComo


There is no question that extended HF bandwidth in sources and electronics is beneficial. Without it the component would not be able to reproduce a square wave which is generally regarded as the acid test for transient accuracy. The extended HF performance of SACD is one reason why it sounds so much better than red book CD.

Agree. Hope no one misses this point. To restate it, a tweeter that responds up to 70,000 hz is a faster tweeter than one that has an upper limit of of say 20,500 hz.

RuSsMaN

Huh?

HBombToo

I just tripped getting anothe beer! can't waite.

Twin

DarqueKnight

I am often sad that my hearing extends just high enough that I can tell how bad most "modern" recordings sound.;)

burdette

Originally posted by dorokusai
But back to the start of the thread,

"Do you think it is a misleading ad?", or would you say its just normal advertising hype???

If the tweeter extends to 70khz, then it does. I reread the ad and it doesn't claim any benefit of the extension.. just states that it exists. From that perspective, it isn't misleading. It does, however, hope that the reader will assume that the extension is a good thing.

I'm not sure how you define hype. If you mean "Exaggerated or extravagant claims made especially in advertising or promotional material" then I don't see it as hype... the only claim is the extension. Hype can also be " a big deal" that isn't necessarily exaggerated. The OJ trial was brimming with hype. To me, there is hype surrounding the Dixie Chicks.

Remember when CDs came out? Suddenly, every piece of equipment was "CD compatible." A pair of headphones being advertised as CD compatible? Didn't mean a thing.. didn't mean extended frequency response, nor anything. Just meant that you can plug these in and listen to a CD!! (and the unsaid part was "just like you can with any pair of headphones you already own!). THAT was hype because *everyone* was making the claim about any product they chose, and it didn't mean anything specific. Similarly with "dolby digital compatible"... a pair of cheapo speakers is DD compatible? Doesn't mean ANYTHING except they'll play all right if you're watching a DVD. The extensive nature of these sorts of claims makes them hype, in my opinion.

dorokusai

Burdette - I understand where you are coming from. I just find comments like what is stated in that ad, disheartening, as an avid and knowledgeable audio enthusiast.

Its all good, that is the type of opinion I am looking for, thanks.